Chapter 4: Conformations

Question 1

What are two types of conformations?

Rotations on a single bond

Answer 1

Staggered (opposite)
Eclipsed (same)

Question 2

What type of conformation is more stable? Why?

Answer 2

Staggered, less sterical strain

Question 3

What are Gauche and Anti conformations?

Answer 3

Gauche: methyl groups forced closer together
Anti: methyl groups on opposing sides

Question 4

Is Gauche or Anti more stable? Why?

Answer 4

Anti, less sterical strain

Question 5

In a chair conformation, axial bonds face…

Answer 5

directly up and down

Question 6

In a chair conformation, equatorial bonds face…

Answer 6

left and right

Question 7

What happens when carbons are “rotated up” in a chair conformation?

Chair flip

Answer 7

Axial and equatorial bonds are shifted, up/down position is not shifted

Ex: Equatorial down –> Axial down

Question 8

Where is the equilibrium shifted for substituted chair conformations?

Answer 8

The substituent favors the equatorial positions

Question 9

In cis chair configuration…

Answer 9

both groups are pointing up or down

(not both axial/equatorial)